Season the chicken with 1 teaspoon ground coriander, 1/2 teaspoon salt and a few grinds of pepper. Heat a large skillet over medium-high heat. Add 2 tablespoons olive oil. Add the chicken and cook until browned, 1 to 2 minutes per side; remove to a plate.
Reduce the heat to medium and add the remaining 1 tablespoon olive oil, the fennel chunks, leeks and garlic; season with the remaining 1/2 teaspoon coriander, 1/4 teaspoon salt and a few grinds of pepper. Cook, stirring occasionally, until the vegetables start to wilt and brown, about 3 minutes. Add the olives and lemon slices and cook until the lemons brown around the edges, about 2 minutes.
Return the chicken to the skillet and add the chicken broth. Bring to a simmer. Cover and cook until the chicken is cooked through and the vegetables are tender, about 15 minutes. Uncover and increase the heat to medium high; bring to a boil and cook until the sauce is reduced, 2 to 3 minutes. Stir in the fennel fronds. Top each serving with parsley.